19.01.2022 Dimensions of the drive and WT coils.

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 I have been requested to supply the dimensions of the electromagnet coils of my C40A. This would be useful information if one needed to replace damaged or missing coils. Or even planned to build a replica of the WT. Which need not follow the original, mechanical design in other than the basic technique.

 Building a new WT main frame could be based on a heavy plate of steel or aluminium. Water jet or plasma cutting is available as a service. The WT's various components could be mounted on blocks. 

 Even multi-laminated Baltic birch plywood could be used to build up the WT's frame profile. Quite a useful material provided it was glued with a suitable adhesive. Epoxy perhaps?  

 While 3D printing offers an even better chance of matching the original appearance of a WT. Albeit with some considerable complication. Digital scanning of an original WT? Not an area with which I am familiar. 

 I have just checked back on my first posts from 2008. The large, pendulum drive coils have a combined resistance of 47 Ohms. These coils are driven by an independent 24V DC supply. NOT the intermittent timekeeping pulse.

 The much smaller, relay electromagnet [WT timekeeping release] has a resistance of 15Ω [Ohms.] Which is rather more than common wall dials. This will require the series time circuit, from the controlling master clock, is set to a current of 0.22 Amps. 

 Note that my coils have been wax coated over the silk wound wire. There is not much left of this protective wax after 80 years of cleaning. 

The earliest WT coils were "naked" wire silk wound. Wax coating lies somewhere in the middle to late 30s and early 40s. Followed by "bandaging" of the coils for even more protection.

 

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